title: Beta2-adrenergic activation via administration of atenolol/formoterol combination increases contractility and coronary blood flow in isolated rat hearts.
abstract: BACKGROUND
  Commonly used adrenergic agonists in low cardiac output scenarios rely primarily on beta1adrenergic activation to stimulate cardiac function. Little is known about the use of beta2-adrenergic agonist administration for this purpose, although the associated vasodilation may be beneficial. This study was conducted in order to assess the efficacy of one such beta2-adrenergic agonist, formoterol, in augmenting cardiac function.
  
  
  METHODS
  The hearts of 8 anesthetized female Wistar rats were excised, and subsequently kept functional in an isolated heart preparation (Langendorff apparatus). After placement on the apparatus, hearts were subjected to the beta1-blocker, atenolol, and then to a combination of formoterol/atenolol. Left ventricular developed pressure (LVDP), heart rate (HR), and coronary flow (CF) were monitored.
  
  
  RESULTS
  CF showed a median increase of 16% (p<0.05) after formoterol/atenolol administration, with this effect lasting 20 min post-administration. Furthermore, statistically significant differences included an early 26% increase in LVDP and a late 21% increase in HR. The CF increase was independent of HR and LVDP changes.
  
  
  CONCLUSIONS
  Our results indicate that the beta2-agonist formoterol not only successfully increases heart rate and contractility, but also increases coronary flow, most likely by means of beta2-mediated coronary vasodilation. This pharmacological profile may prove to be especially beneficial in situations where cardiac output must be increased, while adequate myocardial oxygen delivery needs to be maintained.
authors.affiliation: Department of Medicine, University of Patras, Greece.
authors.forename: Dionysios C
authors.initials: DC
authors.lastname: Watson
authors.forename: Maria
authors.initials: M
authors.lastname: Sargianou
authors.forename: Vassilios
authors.initials: V
authors.lastname: Leivaditis
authors.forename: Constantinos
authors.initials: C
authors.lastname: Anagnostopoulos
mesh_terms: D058671:Adrenergic beta-1 Receptor Antagonists / Q000008:administration & dosage*; D058666:Adrenergic beta-2 Receptor Agonists / Q000008:administration & dosage*; D000818:Animals; D001262:Atenolol / Q000008:administration & dosage*; D003326:Coronary Circulation / Q000187:drug effects / Q000502:physiology*; D004359:Drug Therapy, Combination; D004983:Ethanolamines / Q000008:administration & dosage*; D005260:Female; D000068759:Formoterol Fumarate; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D018343:Receptors, Adrenergic, beta-2 / Q000378:metabolism*
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D058666:Adrenergic beta-2 Receptor Agonists; D004983:Ethanolamines; D018343:Receptors, Adrenergic, beta-2; D001262:Atenolol; D000068759:Formoterol Fumarate